Passage 8.7.8
εἰ δὲ τῶν ἐς Γλαῦκον τὸν Σπαρτιάτην ἐποιήσατο ὁ Φίλιππος λόγον καὶ τὸ ἔπος ἐφʼ ἑκάστου τῶν ἔργων ἀνεμίμνησκεν αὑτόν, ἀνδρὸς δʼ εὐόρκου γενεὴ μετόπισθεν ἀρείων, οὐκ ἂν οὕτω δίχα λόγου δοκεῖ μοι θεῶν τις Ἀλεξάνδρου τε ὁμοῦ τὸν βίον καὶ ἀκμὴν τὴν Μακεδόνων σβέσαι.
But if Philip had taken heed of his treatment of Glaucus the Spartan, and had reminded himself of this saying at each of his actions—that the descendants of a righteous man are made better—then it seems to me beyond doubt that no god would so swiftly have extinguished the life of Alexander and simultaneously ended the glory of the Macedonians.